Thermionic valve



y 1939-v W. DALLENBACH 2,157,952

THERMIONIC VALVE Filed April 16, 1956 s Sheets-Sheet 1 Fig.1

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w. DALLENYBVACH THERMIONIC VALVE Filed April 16, 1936 5 Shee'ts- Sheet 2 Fig. 3

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May 9, W39. w. Di-KLLENBACH THERMIONIC VALVE Filed April 16, 1936 5 Sheets-Sheet s //7 VEI'HOI.

WALTER DALLEN EACH May '9, 1939.

w. DALLENBACH 2 151952 THERMIONIC VALVE 5 Sheets-Sheet 4 Filed'April 16, 1936 Inventor: WALTER DALLENBACH y 1939- w. DALLENBA CH 2,157,952

THERMIONIC VALVE Filed April 16, 1956 5 Sheets-Sheet 5 lnvemor: WALTER DALLENBACH Q 6 hi At orney Patented May 9, 1939 UNlTED STATES 2,157,952 THERMIONIC VALVE Walter Diillenbach, Berlin-Charlottenburg, Germany, assignor to Julius Plntsch Kommanditgesellschait, Berlin, Germany Application April 16, 1936, Serial No. 74,797 In Germany April 18, 1935 12 Claims. (01. 250-215 The present invention concerns valves for ex- An object of the invention is an electronic valve comprising an air-evacuated vessel containing a cathode, a grid and an anode, conductive bodies being connected to the grid and anode and forming, with the electrodes, a hollow body which on its inner surface is entirely, or almost entirely, electrically conductive, and which acts as a resonator, conductors also being provided in the valve and coupling the exciting resonator with the control resonator located between the cathode and the grid.

With the valve according to the invention, selfregulation or self-excitation is for example, possible, the corresponding control 'field being made opposite in direction to the main field owing to the fact that the anode projects into the control space between the grid and cathode.

The electronic valve according to the invention is suited for operation with transmission times of the electrons between the cathode and the anode which are small in relation to the duration of the periods of the excited oscillation, or with electron transmission times that are of small order of magnitude or are larger than theduration'of the periods of the oscillation.

The valve according to the invention has, com pared with the known valves, the advantages of small losses, particularly small radiation and leakage-losses, and, in view of the screening of all the spaces concerned with the exciting of the oscillations, of certainty and constancy oi operation.

In order that the invention may be clearly understood and readily carried into practice, referenoe will now be made to the accompanying drawings, in which various embodiments of the invention are illustrated by way or example and in which: 4

Figures 1 to 4a show, in longitudinal and transverse sections, thermionic valves having cylindrical and concentric electrodes and an excitin resonator consisting of concentric conductors.

Figures 5 to 6a show, likewise in longitudinal and transverse sections, thermionicvalves havin cylindrical and concentric electrodes and with an exciting resonator symmetrically located with respect to the electrodes.

' Figures '7 to 8a show valves having disc-shaped resonance spaces and electrodes located symmetrically around the axis.

In the example shown in Figures 1 and 1a, the electrode system used for excitation consists of the hairpin-like cathode l, the cylindrical grid 2 concentrically surrounding the cathode, and the cylindrical anode 3 that is concentric relative to 5 said cathode and anode. Thegrid and anode are extended in one direction by concentric conductors l and 5 to form a resonator. The upper end of this resonator is prolonged by a concentric energy conductor. inner conductor of the resonator the inner conductor 4' of the energy line 4', 8, which at the upper end passes into an aerial 6. The outer conductor 5 of the resonator is galvanically connected to the outer conductor 8 of the energy 16 line by way of the flange-like part 1, and the upper end of the outer conductor 8 is joinedto a metal .plate 9 perpendicular to the axis of the valve.

The lower end oi. the anode 3' is closed practically completely by a plate Ill, through which are 0 passed, in the axis of symmetry of the valve, the

. heating leads which are formed outside the valve as concentric conductors II and I2. The tubular outer-conductor II is passed, insulated, through the metal plate In connected to the anode and 25 forms with the cylindrical extension IS a condenser of finite magnitude. The tubular heating supply conductor I l is furthermore surrounded by a metal cylinder ll of about the length M4 that is galvanically connected to the conductor II at 30 the end remote iromfthe valve by a disc-shaped wall ii. The interior of the valve is closed vacuum-tightly by the seal l6 at the place wher the conductor I I is passed into the valve, and by the seal H at the end of the energy line 4', 8. The space between the concentric heating leads II and I2 is filled with an insulating material which also seals the interior of the valve vacuumtightly. An insulating ring i8-is provided at the place where the resonator and the energy line 40 merge into one another for the purpose of at-' taching the inner conductor 4' or 4. To enable a suitable bias to be imparted to the grid electrode a conductor i9 passing through the outer conductor 8 is connected to the conductor 4' at 45' the point where the resonator merges into the energy line, in the potential node. This conductor 19 passes through the outer conductor 8 by way of the vacuum-tight seal 20.

The manner in which this valve functions is as 31,-

follows Assuming that an alternating field exists between the grid 2 and the anode 3, it is found that with the described couplinga field is set up in the control space between the anode and the There is connected to the 10 cathode, which is directed oppositely to the field set up due to penetrance. This consequently gives rise to the conditions favourable for a correctphase controlling potential with a transmission time of the electrons between cathode and anode that is short in comparison to the duration of the oscillations. As the conductor parts between the cathode I and the condenser I3 are short .in comparison to the wave-length, the cathode receives an alternating tension that is of like phase'to the anode. The amplitude of this alternating tension is determined by the magnitude of the condenser l3. Thus, if for example there exists between the anode and the grid a field directed inwards from without, the control field between the cathode and the grid is directed outwardly from within, that is to say oppositely, and it eradicates the harmful eiiect of penetrance, or produces on the cathode a superficial charge of suitable magnitude that controls the space charge. In this example the length of the control space is made short in comparison to the wave-length. The energy line 4', 8 connecting with the resonator in the potential node serves to couple loosely the aerial 6and the .plate 3 acting as counterpoise.

In order to prevent leakage of oscillation energy by way of the heating leads, the two heating leads are formed outside the valve as concentric conductors which mutually form a short-circuit condenser. Further, the outer conductor ll forms with the'hollow cylinder H a resonator of length M4 that acts as achoke element.

Figures 2 and 20. show quite a similar embodiment to that of Figures land In, with the difference that the resonator ll, ll acting as a choke element isdirectly connected to the valve.

The lower end of the anode cylinder 3 is provided with a flange 2|, opposite which is a metal plate the exciting space is set up by the disc-shaped conductor 24 constituting an aperiodic conductor because not tuned to resonance with the operating wave length of the tube, which on the one side is galvanically connected to the tubular heating lead II. and on the other hand is capacitively coupled to the anode through the intermediary of the annular conductor 25. In this case also the length of the actual control space is short in comparison with the length of the resonator, so .thatthe latter cannot additionally excite itself. In addition the cathode is attached to a tension spring 25 inside the control space. In principle the manner in which this arrangement functions is the same as described in connection with Figure 1. The metallic surface at the end of cylinder ll forms a condenser which is cooperatively related to the conductor 2|.

Figures 3 and 3a show an embodiment similar to those of Figures 1 to 20, with the diil'erence that the control space is prolonged to a tuned control resonator so that the latter can be used' as a choke element for the heating leads. The heating leads are therefore passed in the neighbourhood of occurring potential nodes through the spaces passing oscillation energy, so that the difllcultie 'of choking the heating leads are overthe exciting resonator consists of a completely closed vessel-like metal body 26 containing in its interiorthe intermediate conductor 21 connected to the grid electrode. The leads to the hairpinlike cathode l likewise consist of concentric concuit condenseix- The conductor consisting of the two conductors and 30 is insulatedly held in.

the potential node by an insulating ring 3|. In the neighbourhood of the potential node the two heating supply leads 2! and 29 also traverse the spaces passing oscillation energy. The additional coupling between the control resonator and the exciting resonator is set up by a conductor 32 advantageously provided inthe valve, which is connected at its upper end to the cathode and at its lower end to the condenser plate 33. The insulator 34 serves to secure the coupling element 32, 33 or also for securing the cathode.

The manner in which this arrangement functions is quite similar to that of the previously described valves. In addition, by using a separate control resonator attached to the cathode and the grid the advantage is obtained that the coupling between the exciting resonator and the control space can be made very loose. Furthermore the influence of the additional coupling elements on the wave length produced is slight,

In the examples hereinbefore described the additional coupling of the control space to the exciting resonator has been by means of aperiodic conductors by way of theelectrical alternating fleld. 1

In contrast to this, Figures 4 and 4a show an exemplary embodiment in which the control space is coupled to the exciting resonator by way of conductorsof resonance length. As in the example according to Figures 3 and 3a the exciting resonator consists of a vessel-like hollow metallic body 26 and a cylindrical inner conductor 21. As in the example of Figure 3, the control resonator is wholly located within the exciting resonator and is bounded by the concentric conductors 21 and 28. The lower ends of the conductors 21, 26 and 28 are again provided with anode v .If a potential loop occurs between the anode and the lower end of the exciting resonator, and a potential node at the upper end at the place of transition into the coupling channel, a potential loop also occurs at the upperend of the looplike coupling channel, over which loop the control resonator is coupled to the exciting resonator. A potential node again occurs at the place of transition of the coupling channel into the control resonator, and a potential loop at the lower end of the control resonator between cathode and grid. Thus the alternating fleld which forms between the grid and the cathode is directed oppositely to that occurring in the control space owing to penetrance. The flow of electrons can thus be controlled in correct phase 'by this control field. It is possible to adjust the correct magnitude of the control amplitude in the control space by suitably selecting the surge impedance of the exciting and controlresonators or of the coupling channel. 1

The energy line 4', 8 by which the aerial 6 or the counterpoise 9 is coupled to the exciting resonator runs concentrically about the coupling channel that connects with the exciting resonator in the potential node. Owing to the fact that the two conducting channels for coupling the control space and for coupling the aerial to the exciting resonator connect parallel thereto in the potential node, the oscillation energy flowing away over these two channels is divided. The distribution of the oscillation energy on to the two lines is brought about by the oscillating current flowing at the upper end of the exciting resonator on the surface of the two conductors 26 and 21 passing partly capacitive'ly between the conductors d, 8 or 8', 35 and flowing round the lower edge of the inner conductor 4'. It is possible, by suitably selecting the surge impedances of these conductors and the connected resonators, to arrange so that the optimum alternating amplitudes occur in the control space of the control resonator, and the aerial is optimumly adapted or tuned to the exciting resonator.

In addition, in this example, the free end of the grid 2 is closed by a metal cap 36, to which the hairpin cathode i is insulatedly attached. One end of the heating filament is joined to the cylindrical conductor 28 which merges, without any variation in cross-section, in the potential node of the control resonator, into the conductor Al", the upper end of which is galvanically connected to the conductor 6' in the interior of the latter. The second heating lead 2;! is passed insulatedly in the interior of the conductor28 as far as the potential node of the control resonator and then, together with the lead 29', is insulatedly passed through the concentric conductors 35, l and 8. The glass seal 20' serves to permit the a vacuum-tight entry of the heating leads 2!! and 29'. The grid electrode also has a voltage lead is in the potential node, this lead passing through the conductors d and 8 and being attached to the conductor 35. The glass seal 2d closes vacuumtightly the place where the lead it passes out of the valve. Thus in this case likewise, by the arrangement of the current or voltage supply leads to the grid and cathode in the potential node of the resonator, the result is obtained that w a maximum leakage losses occurs, and special choke elements are rendered superfluous.

Valves of greater symmetry and fly-wheel resistance are obtained with a resonator tuned to half the wave length. The valves illustrated in Figures 1 to ed, and in particular Figures 1, to 3a, can for example be so constructed that the exciting and control resonators are symmetrically prolonged to a perpendicular plane through the valve in the potential node. The energy line for coupling an aerial could then connect, preferably perpendicularly to the conductors bound ing the exciting resonator adjacent the potential node.

Likewise very symmetrical arrangements with resonators. tuned to M2 but having only one electrode system are illustrated in Figures 5c'.

These figures illustrate an embodiment with an aperiodic and electric coupling between exciting resonator and control space. Figures e and 8c show a valve similar to that of Figures 55a-, but with a coupling channel of resonance length.

In the examples shown in Figures 5 and 5a the electrode system consists'of a filamentary cathode I, a concentric cylindrical grid 2 anda concentric cylindrical anode 3. All the three electrodes are prolonged in both directions by cylindrical conductors to form resonators or to energy lines or short-circuit condensers of resonance length connected thereto. The anode is prolonged to form the cylindrical metallic casing 39, to the lower end of which is attached a cylindrical tube iii of smaller diameter than the outer conductor of the resonator, this tube 40 being closed at its end. The metal tubes 4| and M are connected to the two ends of the grid. The tube M merges, without changing its crosssection, into the tubular element 62 that is likewise closed at its end, while the tube M is prolonged at the end of the valve by the inner conductor l of the energy line. Conductors 43 and in connecting with the cathode are located concentricallywithin the tubes i, M, ti and 42. The cylindrical conductor 43 is prolonged upwardly by the cylindrical conductor id, whilst the likewise cylindrical conductor 3 is prolonged downwardly by the conductor Bil. Thus two resonance spaces are formed which are only coupled together through the gaps in the grid 2. The resonance space acting as exciting resonator is bounded by the grid, anode and conductors 38, M and ti and the resonance space'acting as the control resonator is bounded by the cathode, grid and conductors iL-M', $3 and 43'. The condoctors 60 and 42 or 42 and 44 form short-circuit condensers, tuned to a quarter of the wave length,

supply lead is to the grid and the leads 29, 29' to the cathode are passed vacuum -tightly into the interior of the valve in the lower potential node of the resonators, in the same way as in the example shown in Figure 3. Also rings of insulating material are provided in the potential nodes for supporting the concentric conductors.

Similarly to the example of Figure 2, the aperiodic coupling of the control space to the exciting resonator isefiected by means of short conductor parts 45 connected to the conductors 63 and 63', which pass insulatedly through the conductors 4 i 6' connected to the grid and which are capacitively coupled near the anode-by means of plates 36. The openings 41 through which the The embodiment according'to Figures 6 and 6a corresponds to that of Figures 5 and 50 except that the additional coupling between the exciting resonator and the control space is set up in a difierent manner. In the'presentembodiment the coupling elements 45 and 48 are dispensed with, and instead the tubular conductor 42 is .left open at the lower end of'the resonator and the end of the conductor 48 is in addition i provided with a tube 48 which, with the end of the conductor 44', forms a short-circuit condenser. The cylindrical and tubular conductors 48, 42

and 48 form acoupling channel between the exciting resonator and the control resonator which i 10 has the same eflect as the coupling channel inthe example according to Figure 4. The surge impedance of this coupling channel can again be so selected that the correct amplitude of the alternating tension occurs in the control space the electrodes and of the conductors connected to the electrodes for forming suitable resonance spaces. Closed resonance spaces protected from radiational loaes can be obtained in particular I 80 by means of disc-shaped conductors closed at the edges.

Figures 7 and 7a illustrate a valve of this kind with flatelectrodes and disc-shaped resonance spaces. The constructional elefiients of this valve 85 are a box-like metallic casing .48, having a preferably flat bottom 50 and top and a cylindricaljacket 52, a second metallic casing 53 entirely surrounded by the casing .49 and likewise having a preferably flat bottom 54 and top 40 55 and -a jacket 58, and a flat metal plate 51 entirely enclosed by this casing 53. The diameter of the metal plate 51 is made only slightly smaller than the internal diameter of the casing 58. At its edge thismetal plate is supported 45 away from the casing 53 by insulators 58 in such a manner that a disc-shaped space is formed between the walls 54 and 51 of large surge impedance, and a disc-shaped space between the walls 55 and 51 of small surge impedance, which spaces 50 are in communication with one another through the gap at the edge. Similarly, the diameter of the casing 53 is made only slightlysmaller than that of the casing 48. The casing 53 is also supported away from the walls of the casing 48 at 55 the edge by insulators 58, whereby a disc shaped resonance space of great height and great surge impedance is formed between the walls 50 and 54, and another resonance space of small height and small surge impedance is formed between the 50 walls'5l and 55. Around the axis of symmetry the lower face of the plate 51 carries a flat cathode 65 and the wall54 carries a grid 8|. In the adjacency of the axis the wall- 58 serves as an anode 82. Consequently the disc-shaped res- 05 onance space between the walls 58 and 54 forms the exciting resonator, and the disc-shaped resonance space between the wall 54 and plate 51 forms the control resonator. In the middle of the upper wall 54 of the outer casing an openo ing a: is provided through which an aerial attached to the wall '55 projects to the exterior. The supply leads 85 and 88 to the grid and anode respectively pass through the outer casing and both casings respectively at the edges. 15 As in the previous examples the es are closed by glass seals, so that in this case also the outer casing can be used as a vacuum vessel. The conductors 81 connected to the plate 51 and capacitlvely coupled to theplate 50 serve to set up the additional coupling between the 5 control resonator and exciting resonator.

The manner in which this valve functions is quite similar to that of the examples described with reference to Figures 1, 2 and 3. A potential loop forms near the axis of symmetry in the exciting resonator, and a potential no'dal line forms at the edge, owing to the fact that the plate-like energy line between the conductors 5i and 55 I practically capacltively short-circuits the exciting resonator at the edge. Likewise the control resonator is short-circuited at the edge by the resonance space between 51 and 55, so that this of symmetry and with a nodal lineof the po- 'tential at the edge. For the additional coupling, in the same way as in the preceding examples with aperiodic coupling, an alternating field is set up in the control space which is opposite in direction to the alternating held in the exciting as space. In this example also the coupling of the I control resonator by way of the conductor 81 can be ade loose, since the control resonator has o a small damping and thus rises to high amplitudes even with a weak coupling. ,39

Finally, Figures 8 and 8a show an embodiment similar to that of Figures 7 and 7a, but with the difference that the coupling between the'exciting resonator and control spacetakes place over a coupling channel of resonance length. The con- 3 5 .structional elements of thisvalve consist essentially of the disc-shapedmetal casing 58 comprising a bottom 88 and top I5 and a jacket 80. In the interior of the casing 68 a metal plate 82 of somewhat smaller diameter than the internal diameter of the casing is supported by insulators 8|. Between the plate 82 and the top ill of the casing an insulatedly supported metal plate 83 is located, the diameter of which is approximately only half of that of the casing or the plate 82. Around the axis of symmetry the plate 88 carries a flat cathode 80 and the plate 82 carries a grid 8|. Around the axis of symmetry the lower wall 88 of the casing again acts as an anode 82. The wall 10 of the casing is provided with an opening through which an aerial connected to the plate projects to the exterior. The voltage and heating leads 55 and 86 to the grid and cathode respectively pass at the same distance from the axis perpendicularly through the 55 {8501612308 spaces and, insulated, through the eas- The manner in which as follows:

The space between the casing wall 68 and the so plate 82 forms an exciting resonator whichpscilthis valve functions is' lates in its fundamental oscillation in such a manner that a potential'loop occurs adjacent the axis of symmetryat the place where the electrodes are arranged, a nodal line occurs at the place where 65,

ill)

- tively great surge impedance.

the two resonance spaces separated by the disc 82 have the same diameter, they have exactly the same natural frequency. The natural frequency of the space above the disc 82 is not altered even by the metal plate 83 that is introduced, but this plate divides the part of the upper resonance space between the nodal line and the potential loop in the axis of symmetry into two spaces. The interspace' between the plates 82 and B3 acts as control resonator, while the upper space between 83 and I acts as energy line for coupling the aerial 64 to the exciting resonator. By suitably selecting the distances apart the various interconnected resonance spaces can be given such a surge impedance that optimum control amplitudes occur between cathode and grid, that is to say the aerial is optimumly adapted or tuned to the exciting resonator.

The valves illustrated in Figures 7 to 8d are remarkable in particular for their high flywheel resistance and their. low ohmic losses. The ohmic losses are especially very small when the surfaces. bordering on the resonance spaces are made of good conducting metal and are highly polished. The advantage of low radiational losses and ease in conducting away the anode loss power is common to all the valves which are herein described.

In the embodiments illustrated in the drawings the resonance spaces have approximately the same surge impedance over their entire length.

Resonators of even greater flywheel resistance can be obtained if the resonators are built up of sections of difierent surge impedances in such a way that the section bordering on a potential loop has a relatively small. sur'ge impedance and the section bordering on a potential node has a rela- In such a resonator the losses are especially low.

The thermionic valves in accordance with the present invention are adapted for the production, amplification and reception both of meter-waves, and also of decimeter and centimeter waves. According to the anode potential which is chosen the valves can be so operated that the transmis-.

sion time of the electrons in the exciting space is short or of the same order as the duration of the oscillations. With a short transmission time the requirement of correct-phase excitation of the fields in the control and exciting space is fulfilled. If the transmission time of the electrons in the exciting space-is comparable with the duration of the oscillations, care must be taken that the electrons are of correct phase when entering this space. This may for example be effected by passmg the electrons through a further space after they leave the control space, and only enter the exciting space after they have passed through a second grid. The valve may also be operated in what is known as a higher oscillation range,'in which case the transmission time of the electrons in the exciting space is approximately an integral multiple of the duration of the oscillations, so that it is possible to work with substantially smaller anode potentials. The exact value of the most favourabie transmission time is best determined experimentally.

The principle of the present invention may also be used in connection with the decimeter and centimeter range in brake-field valves having a positive grid and an anode which is only slightly positive or negative. In such cases a negative control grid bounding the control space is suitably inserted between the positive grid and the cathode. Particularly advantageous constructions are obtained if a special and, in particular an aperiodic, acceleration space is provided between the control and exciting space. Furthermore, special space charge or screening grids may be embodied in the valve, especially in the case of amplifying and receiving systems.

What I claim is:

1. A valve, comprising an anode, a vacuum containerand a control electrode, a first conductor connected with said anode, a second conductor connected with said control electrode, said conductors forming a hollow body, the inner surface of which is substantially wholly electrically conductive and which surroundsan exciting resonator space, and a. condenser coupling.

said exciting resonator space to the control space situated between said cathode and control electrode.

2. A valve comprising an anode in the form of a vacuum container, a cathode within the anode, a grid between said cathode and anode, a first conductor connected to said anode, a second conductor connected to said grid, said conductors forming a hollow body the inner surface of which is substantially wholly electrically conductive and which surrounds an exciting resonator space, conductors connected to said cathode and grid and forming a second hollow body the inner surface of which is substantially wholly electrically. conductive, and condenser means coupling said ,exciting resonator space to the control space situated between said grid and cathode. v

3. A valve, comprising an anode, a vacuum container and a control electrode, a first conductor connected with said anode, a second con- -ductor connected with said control electrode, said conductors forming a hollow body the inner surface of which is substantially wholly electrically conductive and which surrounds an. exciting resonator space a third conductor connected with said cathode, said third conductor together with the conductor connected to the control electrode and the conductor connected with the cathode forming a second hollow body,

the inner surface of which is electrically conducted said second hollow body being detuned relative to the natural frequency of the exciting resonator, and condenser means coupling said exciting resonator to the control space situated between said cathode and control electrode. 4. A valve, comprising an anode, a vacuum container and a control electrode. a. first conductor connected with said anode, a second conductor connected with said control electrode, said conductors forming a hollow body the inner surface of which is substantially wholly electrically conductive and which surrounds an ex: citing resonator space, a third conductor connected with said cathode, said third conductor together with theconductor connected to the control electrode and the conductor connected with the cathode forming a second hollow body, the inner surface of which is electrically-conducted said second hollow body being tuned relative to the natural frequency of the exciting resonator spaceand forming a control resonator, and condenser means coupling said exciting resonator to the control space situated between said cathode and control electrode.

5. A valve comprising an anode in the form of a vacuum container, a cathode within the anode, a grid between said cathode and anode, a. first conductor connected to said anode, a secductors forming a hollow body the inner surface of which is substantially wholly electrically conductive and which surrounds an exciting resonator space, and aperiodic conductors, comprising a condenser, coupling said exciting resonator to the control space situated between said cathode and grid, said last-named conductors being short in comparison with the wave-length of the exciting resonator. e

'7. A valve comprising an anode in the form of a vacuum container, a.cathode within the anode, a grid between said cathode and anode, a first conductor connected to said anode, a second conductor connected to said grid, said conductors forming a hollow body theinner surface of which is substantially wholiyelectrically conductive and which surrounds an exciting resonator, and aperiodic conductors, including a condenser, coupling said exciting resonator to the control space situated between said cathode and grid, said last-named conductors being short in comparison with the wave-length of the exciting resonator and being coupled to the electric alternating field of said exciting resonator.

8. A valve comprising an anode in the form of a vacuum container, akcathode, a grid within the anode and arranged coaxially therewith, concentric conductors connecting'with said grid and anode and forming with the latter an exciting resonator space, an aperiodic conductor,

including a condenser, coupling said anode to said cathode, supply leads connecting ,to said cathode, and a choke element on said supply leads, the conductors defining the said exciting resonator forming a hollow body the inner surface of which is substantially wholly electrically conductive.

9. A valve comprising an anode in the form of a vacuum container, a cathode, a grid within the anode and arranged coaxially therewith,

concentric conductors connecting with said grid and anode and forming with the latter an exciting resonator space, an aperiodic conductor,

leads, the conductors defining the said exciting resonator forming a hollow body the inner surface of which is substantiallywholly electrically conductive, and a concentric high frequency line of relatively low surge impedance connecting to said exciting resonator in the potential node.

10,.A valve comprising an anode in the form of a vacuum container, a cathode, a grid within the anode and arranged coaxially therewith, concentric conductors connecting with said grid and anode and forming with the latter an exciting resonator space, an aperiodic conductor, including condenser means, coupling, said anode to said cathode, supply leads connecting to said cathode, and a choke element on said supply leads, the conductors defining the said exciting resonator forming a hollow body the inner surface of which is substantially wholly electrically conductive, said choke element comprising an outer conductor and an inner conductor, the outer conductor being capacitively connected to said anode and the inner conductor being galvanically connected to a cathode supply lead. 11. A valve comprising an anode in the form of a vacuum container, an. inner, an intermediate and an outer conductor, said conductors being arranged concentrically with said anode a cathode at the end of said inner conductor, a grid at the corresponding end of said intermediate conductor, and the anode at the corresponding end of said outer conductor, a conductor closing the open end of said anode, said grid at the corresponding. e d of said intermediate conductor, and the anode at the corresponding end of said outer conductor, a conductor closing the open end ofsaid anode, a con-v centric'high-frequency energy line of relatively low surge impedance connecting to the outer and intermediate conductors at the ends remote from the electrodes, said grid, anode, outer and intermediate conductors defining an exciting resonator space, and said cathode, grid, intermediate and inner conductors defining a control resonator space, and a conductor, short in comparison to the wave-length, galvanically connected to said cathode and coupled to said anode in the neighbourhood of the anode by means of a condenser.

WALTER DAlLENBACH. 

